io6 



The lournal of Heredity 



ONE OF THE TWO COMMON TYPES OF CALVEb PRODUCED 

 The white belt pattern which is such a striking feature of the Helted cattle is entirely absent 

 in this type of calf. \'et this type is commonly produced, even when both parents are belted. 

 They occur less frequently, however, when the belted cattle are bred true for a considerable length 

 of time, and more frequently after the introduction of fresh blood. (Fig. 6.) 



toward the belted pattern, whereas the 

 bull in Mr. Hmnvink's experiment was 

 undoubtedly heterozygous. For these 

 reasons we cannot draw any inferences 

 relative to Mr. Jochems' breeding. 



IRREGULAR COLOR PATTERNS 



A very notable feature of the calves 

 thus produced, however, is that for the 

 greater part they showed very serious 

 pattern deviations. This i^henomenon 

 is of frequent occurrence, which was 

 corroborated by the additional evi- 

 dence produced by Mr. Van Muilwijk, 

 Secretary to the Herd-book of Belted 

 Cattle at Leerdam. When such an 

 irregularly belted animal, that is Fi 

 from belt X pied, is crossed back with 

 a pied one, its calf is often more purely 

 belted than the [)ar('nt. We may there- 

 fore suppose that the pattern deviation 

 is at least to some extent a modification. 

 Further statements which I have set 



forth more in detail in Genetica con- 

 fimi my experiences. 



Of the cross belt X black only a few 

 cases are known to me with certainty. 

 From this cross I am not yet ac- 

 quainted with the occurrence of pied 

 calves. 



It remains for us to consider the 

 cross, black X black, black X belt, 

 and black X pied, as well as their 

 reciprocal crosses. It is not until this 

 has been done that a supposition can 

 be made with an>' amount of certainty 

 concerning the genetic composition of 

 our breeds. Everybody knows, how- 

 ever, that in practice it is often very 

 difficult to carry out experiments with 

 cattle. For this reason I shall not wait 

 until such time as the otlur experi- 

 ments should have been carried out, 

 but proceed to set ft)rth what is to be 

 considered probable on the ground of 

 what we know at present. 



